1. Field of the Invention
The present invention relates to an antenna member (hereinafter also referred to as an antenna part material). The antenna member according to the present invention is useful to be applied to a so-called IC card. Particularly, the present invention relates to the art durable for use of a plurality of antenna members piled up with or without intention.
2. Description of the Related Art
Lately, an IC card has been developed which embeds an IC chip (a semiconductor integrated circuit element) and an antenna for wireless transmission and reception of data. These are intended to be widely utilized, for example, for a commutation ticket and a coupon ticket in various transport facilities, a telephone card, an in-and-out card to room, an ID card, a license, or a music ticket, etc. Further typical use of the card intended includes the object for pachinko, a card for recreational facilities such as an amusement park, a theater, and so on, for a medical use, or for various applications of self-governing communities, etc. Thus, the present invention can be applied to these various cards.
As a typical example of an antenna member according to the present invention, there is provided a so-called IC card. FIG. 1 shows a contactless type IC card as one example thereof. FIG. 1 is a plan view showing a conception of the IC card, showing an arrangement of an IC chip 2 and an antenna embedded in an IC card 1. The number of windings of an antenna coil is simplified in the drawing for better understanding of an explanation. In the drawings, for example, FIGS. 9, 12, 13, 14, 15 and 16, showing a card with the similar conception described below, to which similar simplification is likewise applied.
FIG. 2 is an explanatory view showing a usage pattern thereof. In this example, an IC card 4 is not always in contact with a data writer-reader 5 (normally called a reader/writer), and exchanges information by an induction electromagnetic field in communication with an antenna 7 embedded in the IC card 4. Because of this reason, the card of this type is called a contactless type. Within the frame indicated by dotted lines at the upper portion of FIG. 2, an antenna 6 mounted on the reader/writer 5, and an antenna 7 and a rectifying circuit 8 mounted on the IC card 4 are illustrated.
Further, this IC card contains no battery, and a supply of power is received through the antenna 7 from the reader/writer 5 side. That is, a signal Vs from the reader/writer 5 is transmitted to the IC card through the antenna 6. The IC card 4 side takes in this signal by the electromagnetic induction through the antenna 7. Generally, a signal source used on the reader/writer side is 13.5 MHz. At this time, a signal is taken in efficiently by resonance with a resonant frequency of a value close to a signal frequency fs by inductance and condenser C of the antenna 7. The thus taken-in signal can obtain a signal voltage Vout by the rectifying circuit 8 embedded in the IC card 4. This signal voltage Vout is supplied to a circuit for the signal processing embedded in the IC card. The circuit used for this purpose and the aforementioned rectifying circuit are incorporated in the IC chip. In FIG. 2, reference numerals 10 and 10' each designates a reader/writer, and a communication controller included in the IC card, respectively.
The general explanation of the IC card appears, for example, on "Data Carrier (II)," Nihon-Kogyo Press, Tokyo: pp. 137-194 March 1991. Further, an IC card using a thin chip has been proposed in Japanese Patent Application Laid-Open No. Hei3-87299.